#include <bits/stdc++.h>
using namespace std;
double Result(double x){
	return 5*x*x*x-2*x*x+8;
}
double idea(double x1,double x2){
	double y1,midx,midy;
	while(true){
		y1=Result(x1);
		midx=(x1+x2)/2;
		midy=Result(midx);
	    if(midy==0.0||fabs(midy)<10e-5)
	     	return midx;
		else if(y1*midy>0)  x1=midx;
		else  x2=midx;
	}
	
}
int main(){
	double x1,x2,x;
	cin>>x1>>x2;
	x=idea(x1,x2);
	printf("%.3f",x);
	return 0;
}
